Joy stick mechanism



Jan. 30, 1968 M. HATHAWAY JOY STICK MECHANISM 2 Sheets-Sheet 1 Filed Dec. 10, 1965 Merwin L. Hathaway,

INVENTOR.

Jan. 30, 1968 M. HATHAWAY JOY STICK MECHANISM 2 Sheets-Sheet 2 Filed Dec. 10, 1965 Merwin L. Hathaway,

VENTOR United States Patent 3,365,975 JOY STICK MECHANISM Merwin L. Hathaway, Lexington, Mass, assignor, by mesne assignments, to the United Statesof America as represented by the Secretary of the Army Filed Dec. 10, 1965, Ser. No. 513,128 4 Claims. (Cl. 74-471) This invention relates to a joy stick mechanism that has .a universally mounted joy stick with electrical means connected to the mounting means for the joy stick so as to express an instantaneous position of the joy stick in X and Y electrical coordinates.

In a radar system, the need for a device which is capable of directing movement of a display hook or pip on the face of a plan position indicator and for blanking out the display hook or pip when desired has arisen.

Therefore, it is an object of this invention to provide a joy stick mechanism for performing the functions set forth above.

Another object of this invention is to provide a friction braking means for uniformly resisting movement of a joy stick in any direction.

A further object of this invention is to provide a connection between the joy stick and Y axis shaft that prevents backlash.

A still further object of this invention is to provide a joy stick mechanism that is simple in design without sacrifice of rigidity and that has few parts that may be made small in size and from light weight materials.

In accordance with this invention, a joy stick mechanism is provided that has a housing with a joy stick so pivoted therein as to be capable of generating a cone of varying magnitude and with electrical means so connected to the pivotal mounting means for the joy stick as to be capable of expressing any instantaneous position of the joy stick in X and Y electrical coordinates.

In the accompanying drawing forming a part of this specification, and in which like numerals are employed to designate corresponding parts throughout the same:

FIGURE 1 is a perspective view of a joy stick mechanism according to this invention;

FIGURE 2 is a perspective view looking from the bottom of the joy stick mechanism of FIG. 1, with the top and bottom covers removed;

FIGURE 3 is a perspective view looking from the top of the joy stick mechanism of FIG. 1 with the top and bottom covers removed; and

FIGURE 4 is a sectional view taken on line 4-4 of FIG. 2 with the top and bottom covers thereon and showing the joy stick in a vertical position.

The invention may be better understood by referring to FIGURE 1 wherein, numeral 1 designates a housing that has a top cover 3 secured thereto by screws 5 and a bottom cover 7 secured thereto by screws (not shown). A joy stick projects through opening 11 (see FIG. 4) in top cover 3, and a boot 13 is connected at one end to upwardly projecting handle portion 14 (see FIG. 4) of the joy stick and at the other end to flange means on cover 3 to seal opening 11 from foreign material and debris.

Variable resistors 15 and 17 (see FIG. 1) have suitable electrical lead connecting means 19 and are mounted by clamps 21 on two perpendicular sides of housing 1. Variable resistor 15 has a shaft 23 (see FIG. 2) that extends through the housing wall to the interior of the housing, and gear 25 is secured to shaft 23 for turning movement of shaft 23 to adjust variable resistor 15.

Variable resistor 17 has a shaft 27 that extends through the housing wall to the interior of the housing, and gear 29 is secured to shaft 27 for turning movement of shaft 27 and adjustment of variable resistor 17.

3,355,975 Patented Jan. 30, 1968 "ice An X axis shaft 31 is pivotably mounted in housing 1 by bearings 33, 35, and split rings 37, 39 (see FIG. 4). Segmented gear 41 is secured to shaft 31 by set screw 43 and is in meshing engagement with gear 25 to adjust variable resistor 15 in accordance with rotation of shaft 31. A Y axis shaft 45 is pivota-bly mounted in housing 1 by bearings and split rings like those for shaft 31. Segmented gear 47 is secured to shaft 45 near one end thereof by set screw 49. Segmented gear 47 meshes with gear 29 to adjust variable resistor 17 in accordance with rotation of shaft 45.

Shaft 31 is located on an axis that intersects and is perpendicular to the axis of shaft 45. A third shaft 51 is pivotably mounted at a center position of shaft 31 on bearings that are similar to those for shafts 31 and 45. Third shaft 51 has an axis that intersects and is perpendicular to the axis of shaft 31, and is co-axially alignable with the axis of shaft 45. The joy stick is connected in a conventional manner to shaft 51 to define upwardly projecting handle portion 14 and downwardly projecting actuator portion 57. Actuator portion 57 has ball type bearings 59, 61 (see FIG. 4) mounted in tandem thereon for contacting rails 63, 65 on opposite sides of slot 67. Slot 67 is formed in yoke 69 of Y axis shaft 45. Slot 67 is so shaped that the center of the slot describes an arc of a circle which has its center at pivot point 71 (see FIG. 4) of the joy stick. By providing yoke 69 with rails 63, 65 and the joy stick with bearings 59, 61, backlash between the joy stick and Y axis shaft 45 is prevented.

A friction brake body 73 is mounted on the lower end of actuator portion 57 by set screws 75 (see FIG. 2). A bore 77 in body 73 receives spring '79 and shoe or plunger 81 which is preferably made of plastic such as Teflon. Spring 79 biases plunger 81 outwardly of body 73 and into frictional engagement with spherical surface 83 on bottom cover 7 to uniformly resist movement of the joy stick.

A micro switch 85 (see FIG. 2) is secured to body 73 by screws 87, and a spring biased actuator arrangement 89 (see FIG. 4) in the joy stick and push button 91 on the end of the joy stick are used to actuate micro switch 85. Cable 93 (see FIG. 2) has leads that are connected at one end internally of the micro switch, and the other end of each of the leads is connected through an electrical connector 95 to the exterior of the housing.

In operation, the joy stick handle portion 14 is moved manually to the position desired to adjust variable resistors 15, 17 to provide signals for causing a pip or hook to be positioned in accordance with the position of the joy stick on a plan position indicator (not shown). The output resistance of variable resistors 15, 17 is directly proportional to the degrees rotation of its respective X or Y shaft. Once the pip or hook has been placed on the plan position indicator and used as desired, actuation of micro switch 85 by depressing push button 91 causes a circuit (not shown) controlled through electrical connector 95 to be controlled and thereby cause said pip or hook to be blanked out.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the size, shape, and arrangement of parts may be resorted to without departing from the spirit of my invention, or the scope of the subjoined claims.

I claim:

1. A joy stick mechanism including: a housing; first and second shafts rotatably mounted in said housing on intersecting axes and perpendicular to each other; a short shaft rotatably mounted in a portion of said first shaft and on an axis that is alignable co-axially with the axis of said second shaft; said second shaft having opposite end portions that are interconnected by a yoke member that has 9 a a slot therein, said slot being formed with two semicircular rails on opposite sides of the slot, facing in opposite directions toward each other and spaced apart in a radial direction so that the rails do not overlap; a joy stick connected to a central portion of said short shaft, said joy stick having a portion on one side projecting through said slot and a second portion on an opposite side projecting outwardly of said housing to form an actuating handle portion; and two rotatable bearings mounted in tandem on said one side portion of said joy stick with one of said bearings contacting one of said rails and the other of said bearings contacting the other of said rails to provide a close tolerance fit between said one side portion of said joy stick and said rails to prevent backlash between the joy stick and said second shaft.

2. A joy stick mechanism as set forth in claim 1, wherein variable resistors are mounted on said housing, gear means are mounted on each of said first and second shafts with one of said gear means meshing with a first gear connected to one of said variable resistors, and the other of said gear means meshing with a second gear connected to the other of said variable resistors.

3. A joy stick mechanism as set forth in claim 1, Wherein said portion on one side of said joy stick has a microswitch mounted thereon, actuator means mounted in the joy stick and extending out opposite ends thereof for actuating said micro-switch, and leads connected to said micro-switch and to electrical terminals mounted in the side of said housing.

4. A joy stick mechanism as set forth in claim 1 wherein friction brake means is provided for uniformly resisting movement of said joy stick, said friction brake means ineluding a spherical surface on a cover at one end of said housing, means slidably mounting a friction pin on said one side portion of said joy stick and a spring biasing said friction pin into frictional engagement with said spherical surface; wherein variable resistors are mounted on said housing, and gear means are mounted on each of said first and second shafts with one of said gear means meshing with a first gear connected for actuating one of said variable resistors, and the other of said gear means meshing with a second gear connected for actuating the other of said variable resistors; and wherein a second cover is mounted on said housing opposite said first recited cover and a boot sealing between said joy stick and an opening through said second cover.

References Cited UNITED STATES PATENTS 2,379,778 7/1945 Allen 74-471 X 2,762,234 9/1956 Dodd 74-471 X 2,939,332 6/ 1960 Peterson 74-471 X 3,095,754 7/1963 Mayon et al 74-471 3,299,731 1/ 1967 Russell 74471 FRED C. MATTERN, JR., Primary Examiner.

C. F. GREEN, Assistant Examiner. 

